An electronically controlled fuel injection device that achieves reduced component count, simplified construction, and cost reduction while promoting discharge of vapor that is generated in a pressurizing chamber. With a fuel passage from a fuel intake pipe into a pressurizing chamber and a return passage that is a discharge passage for vapor generated in the pressurizing chamber, and a plunger with a prescribed reciprocating operation having a standby position set as a position enabling fuel supply and vapor discharge, the electronically controlled fuel injection device eliminates the need for an inlet check valve and promotes the discharge of vapor that is generated when fuel is supplied from the fuel intake pipe to the pressurizing chamber.